Contents

The peculiar distribution pattern of the mainland boojums has led Mexican botanists to conclude that they were probably transplanted to the mainland by the indigenous Seri people, who lived in this area and still live on communal property south of this location. The Seri name for this plant is cototajSeri pronunciation: [ˈkototax].[5] In Seri belief, touching this plant will cause strong winds to blow (an undesirable state). Given this belief, the hypothesis that the Seri people transplanted it is doubtful.[3]

The Fouquieria columnaris trunk is up to 24 cm thick, with branches sticking out at right angles, all covered with small leaves 1.5–4 cm (0.59–1.57 in) long. They can grow to a height of 20 meters (almost 70 feet). The flowers bloom in summer and autumn; they occur in short racemes, and are creamy yellow with a honey scent.[6]

1.
Baja California Peninsula
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The Baja California Peninsula is a peninsula in Northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California, the peninsula extends 1,247 km from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south. It ranges from 40 km at its narrowest to 320 km at its widest point and has approximately 3,000 km of coastline, the total area of the Baja California Peninsula is 143,390 km2. The peninsula is separated from mainland Mexico by the Gulf of California, there are four main desert areas on the peninsula, the San Felipe Desert, the Central Coast Desert, the Vizcaíno Desert and the Magdalena Plain Desert. The land of California existed as a myth among European explorers before it was discovered, the earliest known mention of the idea of California was in the 1510 romance novel Las Sergas de Esplandián by Spanish author Garci Rodríguez de Montalvo. Its first expedition reached the Gulf of California and California, nevertheless, the idea of the island persisted for well over a century and was included in many maps. 1532, Hernán Cortés sends three ships North along the coast of Mexico in search of the Island of California, the three ships disappear without a trace. 1533, Cortés sends a mission to search for the lost ships. Pilot Fortún Ximénez leads a mutiny and founds a settlement in the Bay of La Paz before being killed,1539, Francisco de Ulloa explores both coasts. 1690s–1800s, Spanish settlement and colonization in lower Las Californias, the first Spanish missions in Baja California are established by Jesuit missionaries,1701, The first report and a map showing California as a peninsula rather than an island is sent to Europe. 1767, Jesuits expelled, Franciscans take over the Baja missions,1769, Franciscans go with the Portola expedition to establish new missions in Alta California. Control of the existing Baja missions passes to the Dominican Order,1773, Francisco Palóus line demarcates Franciscan and Dominican areas of mission control. 1804, Las Californias divided into Alta and Baja California, using Palóus line, 1810–1821, Mexican War of Independence 1821, First Mexican Empire, Baja California Territory established, covering Baja California Peninsula. 1847, The Battle of La Paz and the Siege of La Paz occurs,1848, Treaty of Guadalupe Hidalgo cedes Alta California to the United States. As a U. S. territory it receives the California Gold Rush,1850, California admitted to U. S. statehood. 1853, William Walker, with 45 men, captures the city of La Paz. Mexico forces him to retreat a few months later, 1930–31, The Territory of Baja California is further divided into Northern and Southern territories. 1952, The North Territory of Baja California becomes the 29th State of Mexico, the southern portion, below 28°N, remains a federally administered territory

2.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate

3.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms

4.
Flowering plant
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The flowering plants, also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approx. 13,164 known genera and a total of c.295,383 known species, etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term angiosperm comes from the Greek composite word meaning enclosed seeds, the ancestors of flowering plants diverged from gymnosperms in the Triassic Period, during the range 245 to 202 million years ago, and the first flowering plants are known from 160 mya. They diversified extensively during the Lower Cretaceous, became widespread by 120 mya, angiosperms differ from other seed plants in several ways, described in the table. These distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants, the amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms. The vascular bundles of the stem are arranged such that the xylem and phloem form concentric rings, in the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium, the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Among the monocotyledons, the bundles are more numerous in the stem and are scattered through the ground tissue. They contain no cambium and once formed the stem increases in diameter only in exceptional cases, the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species, the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf, occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. There are two kinds of cells produced by flowers. Microspores, which divide to become pollen grains, are the male cells and are borne in the stamens. The female cells called megaspores, which divide to become the egg cell, are contained in the ovule. The flower may consist only of parts, as in willow. Usually, other structures are present and serve to protect the sporophylls, the individual members of these surrounding structures are known as sepals and petals. The outer series is usually green and leaf-like, and functions to protect the rest of the flower, the inner series is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators, attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower

5.
Tree
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In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. Trees are not a group but include a variety of plant species that have independently evolved a woody trunk. In looser senses, the palms, the tree ferns, bananas. Trees tend to be long-lived, some reaching several thousand years old, the tallest known tree, a coast redwood named Hyperion, stands 115.6 m high. Trees have been in existence for 370 million years and it is estimated that there are just over 3 trillion mature trees in the world. A tree typically has many secondary branches supported clear of the ground by the trunk and this trunk typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark which serves as a protective barrier, below the ground, the roots branch and spread out widely, they serve to anchor the tree and extract moisture and nutrients from the soil. Above ground, the divide into smaller branches and shoots. The shoots typically bear leaves, which light energy and convert it into sugars by photosynthesis, providing the food for the trees growth. Flowers and fruit may also be present, but some trees, such as conifers, instead have pollen cones and seed cones, others, such as tree ferns, trees play a significant role in reducing erosion and moderating the climate. They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues, trees and forests provide a habitat for many species of animals and plants. Tropical rainforests are one of the most biodiverse habitats in the world, trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses. In parts of the world, forests are shrinking as trees are cleared to increase the amount of available for agriculture. Because of their longevity and usefulness, trees have always revered, with sacred groves in various cultures. Although tree is a term of common parlance, there is no universally recognised precise definition of what a tree is, either botanically or in common language. In its broadest sense, a tree is any plant with the form of an elongated stem, or trunk. Trees are also defined by height, with smaller plants from 0.5 to 10 m being called shrubs

6.
Fouquieria splendens
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Fouquieria splendens is a plant indigenous to the Sonoran Desert and Chihuahuan Desert in the Southwestern United States, and northern Mexico. Ocotillo is not a true cactus, for much of the year, the plant appears to be an arrangement of large spiny dead sticks, although closer examination reveals that the stems are partly green. With rainfall, the plant quickly becomes lush with small, ovate leaves, individual stems may reach a diameter of 5 cm at the base, and the plant may grow to a height of 10 m. The plant branches very heavily at its base, but above that, the branches are pole-like and rarely divide further, the leaf stalks harden into blunt spines, and new leaves sprout from the base of the spine. The bright crimson flowers appear especially after rainfall in spring, summer, flowers are clustered indeterminately at the tips of each mature stem. Individual flowers are zygomorphic and are pollinated by hummingbirds and native carpenter bees. Planting ocotillo can be done year-around with care, ideal plants have been grown from stem cuttings and from seed. Transplanting large bare-root plants has marginal success, if their direction is not marked, success is again limited. Ocotillo plants prefer well-drained, sandy or gravely loam soil with low to moderate amounts of organic content, ideal locations are sunny, open, unrestricted and those where surface water does not collect. Transplanted plants require irrigation to become established, but once established, individual ocotillo stems are sometimes used as poles as a fencing material in their native region, and often take root to form a living fence. Due to their weight and interesting pattern, ocotillo branches have been used for canes or walking sticks. Fresh flowers are used in salads and have a tangy flavor. Flowers are collected, dried, and used for tisanes, according to Medicinal Plants of the Desert and Canyon West, a fresh bark tincture can be made by chopping or snipping freshly removed bark into 1/2-inch pieces. This is believed to stimulate better visceral lymph drainage into the thoracic duct, bathing in water that contains crushed flowers or roots has been used to relieve fatigue. Native Americans are known to place the flowers and roots of ocotillo over fresh wounds to slow bleeding, Ocotillo is also used to alleviate coughing, achy limbs, varicose veins, urinary tract infections, cervical varicosities, and benign prostate growths. The three subspecies are, F. s. splendens Engelm, F. s. breviflora Hendrickson F. s. org, Fouquieria splendens Ocotillo in Joshua Tree National Park UC CalPhotos gallery of Fouquieria splendens

7.
Sonora
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Sonora, officially the Free and Sovereign State of Sonora, is one of 31 states that, with Mexico City, comprise the 32 federal entities of Mexico. It is divided into 72 municipalities, the city is Hermosillo. Sonora is located in Northwest Mexico, bordered by the states of Chihuahua to the east, Baja California to the northwest and Sinaloa to the south. To the north, it shares the U. S. –Mexico border with the states of Arizona and New Mexico, and on the west has a significant share of the coastline of the Gulf of California. Sonoras natural geography is divided into three parts, the Sierra Madre Occidental in the east of the state, plains and rolling hills in the center, and the coast on the Gulf of California. It is primarily arid or semiarid deserts and grasslands, with only the highest elevations having sufficient rainfall to support other types of vegetation, Sonora is home to eight indigenous peoples, including the Mayo, the Yaqui, and Seri. It has been important for its agriculture, livestock, and mining since the colonial period. With the Gadsden Purchase, Sonora lost more than a quarter of its territory, from the 20th century to the present, industry, tourism, and agribusiness have dominated the economy, attracting migration from other parts of Mexico. Several theories exist as to the origin of the name Sonora and they encountered the Opata, who could not pronounce Señora, instead saying Senora or Sonora. A third theory, written by Father Cristóbal de Cañas in 1730, states that the name comes from the word for a water well, sonot. The first record of the name Sonora comes from explorer Francisco Vásquez de Coronado, Francisco de Ibarra also traveled through the area in 1567 and referred to the Valles de Señora. Evidence of human existence in the dates back over 10,000 years. The first humans were hunter gatherers who used tools made from stones, seashells. During much of the period, the environmental conditions were less severe than they are today, with similar. The oldest Clovis culture site in North America is believed to be El Fin del Mundo in northwestern Sonora and it was discovered during a 2007 survey. It features occupation dating around 13,390 calibrated years BP, in 2011, remains of Gomphothere were found, the evidence suggests that humans did in fact kill two of them here. Agriculture first appeared around 400 BCE and 200 CE in the river valleys, the lowland central coast, however, seems never truly to have adopted agriculture. Because Sonora and much of the northwest does not share many of the traits of that area

8.
Mexico
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Mexico, officially the United Mexican States, is a federal republic in the southern half of North America. It is bordered to the north by the United States, to the south and west by the Pacific Ocean, to the southeast by Guatemala, Belize, and the Caribbean Sea, and to the east by the Gulf of Mexico. Covering almost two million square kilometers, Mexico is the sixth largest country in the Americas by total area, Mexico is a federation comprising 31 states and a federal district that is also its capital and most populous city. Other metropolises include Guadalajara, Monterrey, Puebla, Toluca, Tijuana, pre-Columbian Mexico was home to many advanced Mesoamerican civilizations, such as the Olmec, Toltec, Teotihuacan, Zapotec, Maya and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its base in Mexico-Tenochtitlan, Three centuries later, this territory became Mexico following recognition in 1821 after the colonys Mexican War of Independence. The tumultuous post-independence period was characterized by instability and many political changes. The Mexican–American War led to the cession of the extensive northern borderlands, one-third of its territory. The Pastry War, the Franco-Mexican War, a civil war, the dictatorship was overthrown in the Mexican Revolution of 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the countrys current political system. Mexico has the fifteenth largest nominal GDP and the eleventh largest by purchasing power parity, the Mexican economy is strongly linked to those of its North American Free Trade Agreement partners, especially the United States. Mexico was the first Latin American member of the Organisation for Economic Co-operation and Development and it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts. By 2050, Mexico could become the fifth or seventh largest economy. The country is considered both a power and middle power, and is often identified as an emerging global power. Due to its culture and history, Mexico ranks first in the Americas. Mexico is a country, ranking fourth in the world by biodiversity. In 2015 it was the 9th most visited country in the world, Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus and the Pacific Alliance. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely, the Valley of Mexico, and its people, the Mexica and this became the future State of Mexico as a division of New Spain prior to independence. It is generally considered to be a toponym for the valley became the primary ethnonym for the Aztec Triple Alliance as a result. After New Spain won independence from Spain, representatives decided to name the new country after its capital and this was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan

9.
Lewis Carroll
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Charles Lutwidge Dodgson, better known by his pen name Lewis Carroll, was an English writer, mathematician, logician, Anglican deacon, and photographer. He is noted for his facility at word play, logic, There are societies in many parts of the world dedicated to the enjoyment and promotion of his works and the investigation of his life. Dodgsons family was predominantly northern English, with Irish connections, conservative, most of Dodgsons male ancestors were army officers or Church of England clergy. His great-grandfather, also named Charles Dodgson, had risen through the ranks of the church to become the Bishop of Elphin. His paternal grandfather, another Charles, had been an army captain, the older of these sons – yet another Charles Dodgson – was Carrolls father. He went to Westminster School and then to Christ Church, Oxford and he reverted to the other family tradition and took holy orders. He was mathematically gifted and won a double first degree, which could have been the prelude to a brilliant academic career, instead, he married his first cousin Frances Jane Lutwidge in 1830 and became a country parson. Dodgson was born in the parsonage at Daresbury in Cheshire near the towns of Warrington and Runcorn. When Charles was 11, his father was given the living of Croft-on-Tees in North Yorkshire, and this remained their home for the next 25 years. He was High Church, inclining to Anglo-Catholicism, an admirer of John Henry Newman and the Tractarian movement, Young Charles was to develop an ambiguous relationship with his fathers values and with the Church of England as a whole. During his early youth, Dodgson was educated at home and his reading lists preserved in the family archives testify to a precocious intellect, at the age of seven, he was reading books such as The Pilgrims Progress. He also suffered from a stammer – a condition shared by most of his siblings – that often influenced his life throughout his years. At the age of twelve, he was sent to Richmond Grammar School at nearby Richmond, in 1846, Dodgson entered Rugby School where he was evidently unhappy, as he wrote some years after leaving, I cannot say. That any earthly considerations would induce me to go through my three years again, I can honestly say that if I could have been. Secure from annoyance at night, the hardships of the daily life would have been comparative trifles to bear, scholastically, though, he excelled with apparent ease. I have not had a promising boy at his age since I came to Rugby. He left Rugby at the end of 1849 and matriculated at Oxford in May 1850 as a member of his fathers old college, after waiting for rooms in college to become available, he went into residence in January 1851. He had been at Oxford only two days when he received a summons home and his mother had died of inflammation of the brain – perhaps meningitis or a stroke – at the age of 47

10.
The Hunting of the Snark
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The Hunting of the Snark is a poem written by Lewis Carroll, the pen name of Charles Lutwidge Dodgson. It is typically categorized as a nonsense poem, written from 1874 to 1876, the poem borrows the setting, some creatures, and eight portmanteau words from Carrolls earlier poem Jabberwocky in his childrens novel Through the Looking Glass. Henry Holiday, the illustrator of the poem, thought of it as a tragedy, the plot follows a crew of ten trying to hunt the Snark, an animal which may turn out to be a highly dangerous Boojum. The only one of the crew to find the Snark quickly vanishes, the poem is dedicated to young Gertrude Chataway, whom Carroll met at the English seaside town Sandown in the Isle of Wight in 1875. Included with many copies of the first edition of the poem was Carrolls religious tract, the Hunting of the Snark was published by Macmillan in the United Kingdom in late March 1876, with illustrations by Henry Holiday. It had mixed reviews from reviewers who found it strange, the first printing of The Hunting of the Snark consisted of 10,000 copies. There were two reprintings by the conclusion of the year, in total, the poem was reprinted 17 times between 1876 and 1908. Carroll often denied knowing the meaning behind the poem, however, in an 1896 reply to one letter, scholars have found various meanings in the poem, among them existential angst, an allegory for tuberculosis, and a mockery of the Tichborne case. The Hunting of the Snark has been alluded to in works and has been adapted for musicals, opera, plays. The Hunting of the Snark shares its setting with Lewis Carrolls earlier poem Jabberwocky published in his childrens novel Through the Looking-Glass. Eight nonsense words from Jabberwocky appear in The Hunting of the Snark, bandersnatch, beamish, frumious, galumphing, jubjub, mimsiest, outgrabe, the Bellman warns them that some Snarks are highly dangerous Boojums, causing the Baker to faint. Once revived, the Baker recalls that his uncle warned him if the Snark turns out to be a Boojum, the hunter will softly and suddenly vanish away. The Baker confesses that the notion of this sudden vanishment brings him much distress, along the way, the Butcher and Beaver, previously mutually wary, become fast friends, after the Butcher teaches it more in ten minutes than it could learn from books in seventy years. The Barrister, meanwhile, dreams of the trial of a pig accused of deserting its sty. The Snark, however, finds the pig guilty and sentences it to transportation and his dream concludes with the jailer informing the court that the pig has actually been dead for years, to the judges disgust. During the hunt, the Banker finds himself attacked by a bandersnatch, two explanations of which event in Carrolls life gave rise to The Hunting of the Snark have been offered. Biographer Morton N. Cohen connects the creation of The Hunting of the Snark with the illness of Carrolls cousin and godson, on 17 July 1874, Carroll travelled to Guildford, Surrey, to care for him for six weeks, while the young man struggled with tuberculosis. The next day, while taking a walk in the morning after only a few hours of sleep, Carroll thought of the final line, For the Snark was a Boojum

11.
Leaf
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A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot, Leaves are collectively referred to as foliage, as in autumn foliage. Although leaves can be seen in different shapes, sizes and textures, typically a leaf is a thin, dorsiventrally flattened organ, borne above ground. Most leaves have distinctive upper surface and lower surface that differ in colour, hairiness, broad, flat leaves with complex venation are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In others, such as the clubmosses, with different evolutionary origins, some leaves, such as bulb scales are not above ground, and in many aquatic species the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls, furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from both in their structure and origin. Many structures of plants, such as the phyllids of mosses and liverworts and even of some foliose lichens. Leaves are the most important organs of most vascular plants and these are then further processed by chemical synthesis into more complex organic molecules such as cellulose, the basic structural material in plant cell walls. The plant must therefore bring these three together in the leaf for photosynthesis to take place. Once sugar has been synthesized, it needs to be transported to areas of growth such as the plant shoots and roots. Vascular plants transport sucrose in a tissue called the phloem. The phloem and xylem are parallel to each other but the transport of materials is usually in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much as the leaf as possible and they are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance plants adapted to windy conditions may have pendent leaves, such as in many willows, the flat, or laminar, shape also maximises thermal contact with the surrounding air, promoting cooling. Functionally, in addition to photosynthesis the leaf is the site of transpiration and guttation. Many gymnosperms have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and these are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. For xerophytes the major constraint is not light flux or intensity, some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides

12.
Flower
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A flower, sometimes known as a bloom or blossom, is the reproductive structure found in plants that are floral. The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs, Flowers may facilitate outcrossing or allow selfing. Some flowers produce diaspores without fertilization, Flowers contain sporangia and are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds, the essential parts of a flower can be considered in two parts, the vegetative part, consisting of petals and associated structures in the perianth, and the reproductive or sexual parts. A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk, each of these kinds of parts is arranged in a whorl on the receptacle. The four main whorls are as follows, Collectively the calyx, corolla, the next whorl toward the apex, composed of units called petals, which are typically thin, soft and colored to attract animals that help the process of pollination. Androecium, the whorl, consisting of units called stamens. Stamens consist of two parts, a called a filament, topped by an anther where pollen is produced by meiosis. Gynoecium, the innermost whorl of a flower, consisting of one or more units called carpels, the carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. Ovules are megasporangia and they in turn produce megaspores by meiosis which develop into female gametophytes and these give rise to egg cells. The gynoecium of a flower is described using an alternative terminology wherein the structure one sees in the innermost whorl is called a pistil. A pistil may consist of a carpel or a number of carpels fused together. The sticky tip of the pistil, the stigma, is the receptor of pollen, the supportive stalk, the style, becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma. The relationship to the gynoecium on the receptacle is described as hypogynous, perigynous, although the arrangement described above is considered typical, plant species show a wide variation in floral structure. These modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species, the four main parts of a flower are generally defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions and/or look like what is typically another part, in some families, like Ranunculaceae, the petals are greatly reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens that are petal-like, the flowers of Peonies and Roses are mostly petaloid stamens

Diagram of secondary growth in a eudicot or coniferous tree showing idealised vertical and horizontal sections. A new layer of wood is added in each growing season, thickening the stem, existing branches and roots.

Tall herbaceousmonocotyledonous plants such as banana lack secondary growth, and are trees under the broadest definition.

Vein skeleton of a leaf. Veins contain lignin that make them harder to degrade for microorganisms.

Near the ground these Eucalyptus saplings have juvenile dorsiventral foliage from the previous year, but this season their newly sprouting foliage is isobilateral, like the mature foliage on the adult trees above